Boosting CO <sub>2</sub> Photoreduction via Ligand‐Engineered Single‐Atom Cobalt Sites in Covalent Organic Frameworks
Ying Xu, Zhihao Zhao, Yan Wang, Xinbo Ma, Haizhou Liu, Jin‐Song Hu, Huan Wang, Dong Wang
Abstract
Abstract The microenvironment of single‐atom active sites plays a pivotal role in determining the activity and selectivity of the CO 2 reduction reaction (CO 2 RR). Herein, we report a highly efficient single‐atom catalyst, Co‐DABT‐COF, featuring Co(II)‐bithiazole N motifs that achieve exceptional CO 2 photoreduction performance (16.4 mmol g −1 h −1 , 96% selectivity) under visible light irradiation in the presence of a photosensitizer and a sacrificial agent. Through isoreticular design maintaining identical Co‐N 2 O 2 primary coordination, Co‐DABT‐COF exhibits 2.8‐fold higher activity than its bipyridine analogue Co‐Bpy‐COF with Co(II)‐bipyridine N motifs (5.8 mmol g −1 h −1 ). Systematic characterization reveals the 2,2′‐bithiazole ligand significantly enhances charge transfer efficiency and reduces the activation energy barrier for *COOH intermediate formation (0.79 eV versus 1.14 eV). Bader charge analysis demonstrates stronger electron donation from Co sites to CO 2 (0.63 e for Co‐DABT‐COF versus 0.58 e for Co‐Bpy‐COF), facilitating CO 2 activation. This work demonstrates a ligand‐engineering strategy for precisely tuning the electronic structure of single‐atom active sites to achieve efficient CO 2 conversion.